Question

In August in September 2005, hurricanes Katrina and Rita caused extraordinary flooding in New Orleans, Louisiana. Many homes were severely damaged or destroyed, and of those that survived, many required extensive cleaning. It was thought that cleaning flood-damaged homes might present a health hazard due to the large amount of mold present in many of the homes. In a sample of 365 residents of Orleans Parish who had participated in the cleaning of one or more homes, 77 had experienced symptoms of wheezing, and in a sample of 179 residents who had not participated in cleaning, 23 reported wheezing symptoms. Can you conclude that the proportion of residents with wheezing symptoms is greater among those who participated in the cleaning of flood-damaged homes?

a. State whether the test is:

i) a two-sample t-test (independent samples)

ii) a matched pairs

iii) a two sample proportion test

b. Write H0 and H1

c. Using Minitab, list the test statistic the p-value your conclusion: reject H0 or do not reject H0. Note: if α is not provided, use a 0.05 significance level

d.   Write a sentence that explains your conclusion in context with the claim. Include the significance level and p-value in this sentence.

e.   Copy and paste the relevant Minitab output into the document. Answers alone are sufficient, you do not need to copy the exercise into the document.

Answer 1

Ans.

(a). The test is a two sample proportion test.

(b). Hypothesis:-

H0: p1 = p2

H1: p1 > p2

(c) Steps for two proportions test in MINITAB:-

1. Choose Stat > Basic Statistics > 2 Proportions.
2. Choose Summarized data.
3. In First sample, enter numeric values under Trials and under Events.
4. In Second sample, enter numeric values under Trials and under Events.
5. If you like, use any dialog box options, and click OK.

Z = 2.33

P-value = 0.010

Decision:- Since P-value = 0.010 <

Hence, we reject H0 at

(d) . Conclusion:-  

There is sufficient evidence to support the claim that the proportion of residents with wheezing symptoms is greater among those who participated in the cleaning of flood-damaged homes.